1. Field of the Invention
The invention relates to a motor vehicle door lock system with an outside door handle, and at least one sensor for detecting the approach of the hand of an operator to the outside door handle and/or touching and/or activating of the outside door handle.
2. Description of Related Art
Conventional electromechanical motor vehicle door lock systems having a radio remote control but without the passive entry function are generally known. In these conventional vehicle door lock systems, the operator presses a button on the remote control module. This activates the control electronics which passes through its reaction phase immediately. Because of the distance of the operator from the vehicle door, by the time the operator reaches the outside door handle on the motor vehicle door, the reaction phase of the control electronics has long been completed and the motor vehicle lock has been unlocked. By pulling on the outside door handle, the operator opens the motor vehicle door and the motor vehicle lock is opened either mechanically so that the detent pawl is lifted by the motion of the outside door handle, or electromechanically or pneumatically, the outside door handle delivering a control signal to the opening drive to raise the detent pawl.
Control electronics with a passive entry function, also known as an xe2x80x9celectronic keyxe2x80x9d, differ from the above explained conventional motor vehicle door lock systems in that on the remote control module, no manipulation is necessary. Therefore a button need not be pressed to unlock the motor vehicle lock when approaching the motor vehicle. Rather this takes place all by itself when the operator approaches the motor vehicle.
As used herein, a passive entry function is defined especially as automatic data interrogation or identification of an operator held data medium, transponder or the like so as to ascertain whether an operator approaching the motor vehicle or about to open the vehicle or its door is authorized for access. This is generally checked by the corresponding electronics of the motor vehicle. With corresponding authorization of the operator, automatic unlocking of the vehicle lock takes place by a central interlock system which typically opens the door lock of the driver-side door or of the door being approached by the operator and the door with the handle being touched or activated.
A motor vehicle door lock system with a passive entry function for the control electronics requires a certain reaction phase or time which includes a starting interval to activate the system as the data medium or the remote control module approaches, an authorization check interval to check the operator for his/her authorization by using the coding of the signals exchanged between the remote control module and the control electronics, and finally, the actual action interval in which the action such as the unlocking of the motor vehicle lock takes place. A corresponding reaction phase is also required when locking the vehicle door lock system. However, this corresponding reaction phase is less critical because it is essentially unnoticed by the operator.
The length of the reaction phase of roughly a few hundred milliseconds (as compared to conventional motor vehicle door lock systems) is perceived as being long if the starting interval is begun only when the outside door handle is activated. Pulling the outside door handle or the like occur in a passive entry function under certain circumstances when the reaction phase of the control electronics has not yet been completed. In such occurrences, the operator can then become annoyed that he/she must pull the door handle a second time and this is interpreted as a xe2x80x9cmalfunctionxe2x80x9d.
Since the resulting total time of the reaction phase cannot be shortened as much as desired, attempts have already been made to conceal the delay time. The published German patent application DE -A- 195 21 024 discloses a motor vehicle door lock system in which the starting interval and the authorization check interval of the control electronics are shifted into a phase which precedes the actual operation phase which is noticeable to the operator. Then, only the remaining time which corresponds to the reaction time of mechanical, conventional motor vehicle door lock system is noticeable to the operator. A different solution is to have the starting interval of the control electronics initiated not only when the outside door handle is activated, but to use the approach of the hand of an operator to the outside door handle to initiate the starting interval. To do this, the provision of a proximity sensor on the outside door handle is known as disclosed in the published German patent applications DE - A - 197 52 974 and DE - A - 196 17 038. In these references, there is approximately 100 to 150 ms between the sensing of the approaching hand of the operator and the hand actually touching the outside door handle. The starting interval of the control electronics, i.e., the xe2x80x9cawakeningxe2x80x9d of the control electronics, therefore begins so far prior to the actual pulling of the outside door handle that the starting interval, and usually also the authorization check interval, are already completed when the outside door handle is in fact moved by the hand of the operator.
The published German patent application DE - A - 196 17 038 which forms the starting point for the present invention discloses a lock system, especially for motor vehicles, with a passive entry function. One electrode of a capacitive sensor is located on an outside door handle while the other electrode of the capacitive sensor is located on the door-side in order to thereby acquire the approach of the hand of an operator to the outside door handle or in the area between the electrodes and subsequently, to activate the passive entry function.
The use of proximity sensors in motor vehicle door lock systems of the type under consideration entails various difficulties. On the one hand, the proximity sensors have a comparatively high closed-circuit current and on the other hand, it is difficult to set a stable, unequivocal response threshold for such proximity sensors. External effects such as rain, snow, dirt and dust greatly change the measured values in capacitive proximity sensors. Finally, in proximity sensors, the problem of the interfering electromagnetic radiation which they emit cannot be ignored. Therefore, because of these disadvantages, motor vehicle door lock systems with a passive entry function in which only actuation of the outside door handle by the hand of an operator begins the starting interval of the control electronics noted previously have major advantages over systems that utilize proximity sensors.
In addition, in the prior art motor vehicle door lock systems that utilize such proximity sensors, comparatively high complexity is necessary to guarantee proper operation. Furthermore, there is the problem of the comparatively high closed-circuit current. Accordingly, comparatively complex circuitry is necessary which leads to high costs in such systems.
Another problem of the prior art is that it is not possible to distinguish between the approach of the operator to the outside door handle and touching of the outside door handle. Therefore, approaching is acquired with a first sensor while touching or actuating the outside door handle is acquired with yet a second sensor. Accordingly the complexity and costs are further increased.
The primary object of the present invention is to devise a motor vehicle door lock system and a process for controlling such a system so that the approach of the operator (such as his/her hand) to an outside door handle and/or touching and/or activating of the outside door handle, can be easily detected. This detection allows passive entry function of the motor vehicle door lock system to be activated or the starting interval of the control electronics to be initiated.
The aforementioned object and other objects are achieved by a motor vehicle door lock system in accordance with the present invention which includes an outside door handle arrangement and a piezovibration generator.
In contrast to the prior art which uses capacitive sensing to sense the approach to the outside door handle or the touching of the outside door handle, the motor vehicle door lock system in accordance with the present invention causes the outside door handle (or at least a part thereof) to vibrate mechanically. By means of a sensor, the vibration behavior and/or the sound waves caused by the vibration or their reflections is measured in order to acquire the approach to the outside door handle, the touching of the outside door handle, and/or the activation of the outside door handle.
As used herein, xe2x80x9cacquisitionxe2x80x9d is defined especially as making available data or measurement signals, the evaluation of which enables detection or sensing of whether the hand of an operator has approached the outside door handle or is already touching and/or activating it. The evaluation can take place directly in the electronics assigned to the sensor and/or in separate evaluation electronics or the like. Thus, it should be appreciated that the location of such evaluation is not critical to the practicing of the present invention. Such electronics can be readily devised by a person of ordinary skill in the electronics art and thus, need not be detailed here. However, it is advantageous if the evaluation electronics which make available the corresponding detection signal, is integrated into the outside door handle or an outside door handle arrangement.
In accordance with the embodiments of the present invention, touching the outside door handle is detected or acquired preferably by one of the two following possibilities. First, when the hand of an operator touches or activates the outside door handle, the vibration behavior of the outside door handle changes. This can be measured, for example, by acquiring or evaluating the damping behavior, the change of the resonant frequency, the change of the vibration amplitude, or the like. Second, the outside door handle or at least part thereof, is caused to vibrate such that the sound waves, especially in the ultrasonic range, are emitted. Preferably, these sound waves are reflected back again by adjacent areas of the assigned door and these reflected sound waves again striking the outside door handle and/or the sound waves striking the door are measured. When the hand of an operator touches the outside door handle, especially in grasping it or activating it, the aforementioned sound propagation is interrupted. This interruption in the sound propagation can be acquired and evaluated accordingly.
In both of the aforementioned embodiments of the present invention, the sensing of touching takes place in a comparatively simple manner. In addition or alternatively, proximity sensing can take place. To do this, according to the second aforementioned possibility, sound waves are emitted by the outside door handle or part of it. An approaching hand causes reflection of the sound waves. The reflection of the sound waves is acquired, especially the transit time is acquired and evaluated. Thus the approach of the hand of an operator to the outside door handle can be easily detected.
The sensing of touch and/or approach enables early activation of the passive entry function and initiation of the starting interval of the control electronics. Thus, enough time is gained to unlock the motor vehicle lock before the operator in fact actuates the outside door handle to open the corresponding motor vehicle door or the motor vehicle lock. Another aspect of the present invention is that sensing both of approach and proximity can be done very easily. Thus, the corresponding functions of the motor vehicle door lock system, the control electronics or other electronics of the motor vehicle, can be activated in two stages that are staggered in time.
Preferably, a piezovibration generator is used to produce the mechanical vibration. This component is readily available and are inexpensive. Preferably the vibration generator is operated in the ultrasonic range. This is especially advantageous in the emission of sound waves which are not audible by humans. The vibration generator can be made such that on the one hand, it can cause the outside door handle or part thereof to vibrate, and on the other, can directly emit ultrasonic waves. This is advantageous especially in sensing both the approaching and touching of the outside door handle by the operator.
A sensor for acquiring vibration or sound waves is preferably assigned likewise to the outside door handle, and is preferably arranged like the vibration generator in the outside door handle. However, in other embodiments, the sensor could also be located, for example, in an adjacent area of the door such as the handle shell of an outside door handle arrangement or the like. Alternatively, there can be a separate or additional sensor solely for detection of sound waves, especially in the ultrasonic range. One especially simple and economical embodiment utilizes a vibration generator which also functions as the sensor. In particular, in the pulsed generation of vibration, the vibration generator can then operate in the pulse pauses as a sensor.
According to one especially preferred embodiment of the present invention, sensing of touch takes place. As soon as the hand of the operator touches the outside door handle or its vibrating part, the vibration characteristic changes, especially the vibration amplitude but optionally, also in the vibration frequency. This change is evaluated and the result of the evaluation is used to xe2x80x9cawakenxe2x80x9d the control electronics, therefore to initiate the starting interval of the control electronics so that then an authorization check interval can follow. This time gain can be sufficient to allow the starting interval, and generally also the authorization check interval, to be completed before the outside door handle is in fact pulled or actuated. Subjectively, the operator perceives that the motor vehicle door lock reacts immediately and passes through the action interval immediately.
These and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the invention when viewed in conjunction with the accompanying drawings.